Inductor, coil substrate, and method of manufacturing inductor

Abstract

A coil substrate includes: a substrate; a first wiring on a first main surface of the substrate; a second wiring on a second main surface of the substrate; a first insulator covering the first wiring; and a second insulator covering the second wiring. The first wiring includes a first coil portion wound outward from one end, and a first connection portion drawn out from the other end of the first coil portion and connected to a first electrode. The second wiring includes a second coil portion wound outward from one end, and a second connection portion drawn out from the other end of the second coil portion and connected to a second electrode. Respective innermost peripheries of the first coil portion and the second coil portion coincide over the whole circumference, and respective outermost peripheries of the first coil portion and the second coil portion coincide over the whole circumference.

1 . An inductor comprising:
 a coil substrate;   a magnetic core that contains at least part of the coil substrate; and   a first electrode and a second electrode that are connected to the coil substrate,   wherein the coil substrate includes:
 a substrate; 
 a first wiring provided on a first main surface of the substrate; 
 a second wiring provided on a second main surface of the substrate opposite to the first main surface; 
 a first insulator provided on the first main surface and covering the first wiring; and 
 a second insulator provided on the second main surface and covering the second wiring, 
   the first wiring includes a first coil portion wound outward from one end, and a first connection portion drawn out from the other end of the first coil portion and connected to the first electrode,   the second wiring includes a second coil portion wound outward from one end, and a second connection portion drawn out from the other end of the second coil portion and connected to the second electrode, the one end of the second coil portion being electrically connected to the one end of the first coil portion, and   an innermost periphery of the first coil portion and an innermost periphery of the second coil portion coincide with each other over whole circumference, and an outermost periphery of the first coil portion and an outermost periphery of the second coil portion coincide with each other over whole circumference.   
     
     
         2 . The inductor according to  claim 1 ,
 wherein the first coil portion and the second coil portion each include a narrow portion having a predetermined line width and a wide portion having a line width greater than the line width of the narrow portion, and   the following relationship is satisfied:
   1.15<(the line width of the wide portion)/(the line width of the narrow portion)<2.1. 
   
     
     
         3 . The inductor according to  claim 1 ,
 wherein the substrate is formed of an insulating film.   
     
     
         4 . The inductor according to  claim 1 ,
 wherein the first insulator and the second insulator are each formed of a coverlay film.   
     
     
         5 . A method of manufacturing the inductor according to  claim 1 , the method comprising:
 forming the first wiring and the second wiring on the first main surface and the second main surface of the substrate respectively;   forming the first insulator and the second insulator to cover the first wiring and the second wiring respectively; and   forming a through hole in the substrate.   
     
     
         6 . A coil substrate that is at least partly contained in a magnetic core in a state of being connected to a first electrode and a second electrode, the coil substrate comprising:
 a substrate;   a first wiring provided on a first main surface of the substrate;   a second wiring provided on a second main surface of the substrate opposite to the first main surface;   a first insulator provided on the first main surface and covering the first wiring; and   a second insulator provided on the second main surface and covering the second wiring,   wherein the first wiring includes a first coil portion wound outward from one end, and a first connection portion drawn out from the other end of the first coil portion and connected to the first electrode,   the second wiring includes a second coil portion wound outward from one end, and a second connection portion drawn out from the other end of the second coil portion and connected to the second electrode, the one end of the second coil portion being electrically connected to the one end of the first coil portion, and   an innermost periphery of the first coil portion and an innermost periphery of the second coil portion coincide with each other over whole circumference, and an outermost periphery of the first coil portion and an outermost periphery of the second coil portion coincide with each other over whole circumference.   
     
     
         7 . A coil substrate that is connected to a first electrode and a second electrode, the coil substrate comprising:
 a substrate;   a first wiring provided on a first main surface of the substrate;   a second wiring provided on a second main surface of the substrate opposite to the first main surface;   a first insulator provided on the first main surface and covering the first wiring; and   a second insulator provided on the second main surface and covering the second wiring,   wherein the first wiring includes a first coil portion wound outward from one end, and a first connection portion drawn out from the other end of the first coil portion and connected to the first electrode,   the second wiring includes a second coil portion wound outward from one end, and a second connection portion drawn out from the other end of the second coil portion and connected to the second electrode, the one end of the second coil portion being electrically connected to the one end of the first coil portion, and   an innermost periphery of the first coil portion and an innermost periphery of the second coil portion coincide with each other over whole circumference, and an outermost periphery of the first coil portion and an outermost periphery of the second coil portion coincide with each other over whole circumference.